1. Field of the Invention
The present invention relates to a direct accessing apparatus and method of a disk recording and reproducing system, and more particularly, to a direct access apparatus in a disk recording and reproducing system, in which a specific image corresponding to the start portion of a continuous image is captured from the continuous image, and the specific image is then recorded on a specific recording area of a disk together with index image information corresponding to the specific image, so that the position of a corresponding moving image can be directly accessed using index image information in a reproduction mode, and to a direct access method thereof.
2. Description of the Related Art
Generally, recorded information can be reproduced using magnetism or using light. In the recorded information reproducing method using magnetism, the alignment of the polarities of magnetic materials coated on a magnetic medium is detected, and information is reproduced according to a corresponding polarity (or phase). As described above, the alignment of the polarities of magnetic materials is used in this recording method. In this sense, this recording method has a merit in that information can be freely recorded.
In the recorded information reproducing method using light, light is projected onto the recorded surface of a recording medium, and irregular reflection caused by pits manufactured on a recording medium is detected, thereby reproducing information. As described above, pits are fabricated on the recording medium in this method. In this sense, this method has a very excellent information retaining efficiency.
Storage media using light include a compact disk-read only memory (CD-ROM) and a dynamic versatile disk-read only memory (DVD-ROM). CD-ROMs store a great amount of information; about 700 megabytes (Mbytes) per information recording layer.
A typical storage medium includes a plurality of sectors radially partitioned on a storage medium having a circular plate shape, and a plurality of tracks into which the sectors are equally and concentrically divided. A storage medium rotates at about 7200 rpm on average, and a disk reproducing apparatus reproduces information in the shape of a concentric circle in a direction from the center of the storage medium to the outer diameter thereof.
Accordingly, a disk reproducing apparatus must be able to rapidly detect specific information among a great amount of information stored in a storage medium. Recent disk reproducing apparatuses must search for information quickly with a trend toward the acceleration of research into high-speed reproduction of a storage medium.
In particular, there is a recent trend toward generalization of not only CD_ROM drives for simply reproducing a recording medium but also compact disk-recordable (CD-R) drives capable of once recording or compact disk-rewritable (CD_RW) drives which are disk recording and reproducing systems capable of several recordings and reproductions. Hence, many recording apparatuses and methods are well-known in which direct access is provided during recording of data on a disk in order to allow users to directly access the position of a desired recorded image upon reproduction of the disk.
As shown in FIG. 1, in a general disk recording and reproducing system, when a data recording command is applied, a data recoding mode is set up, and as video data and audio data are applied, a video encoder 100 and an audio encoder 101 encode the video data and the audio data, respectively. Then, a data mixer 102 mixes the encoded video data and the encoded audio data. The mixed data is channel-encoded by a channel encoder 103. In the channel encoder 103, an address on a disk 109 is applied to the mixed data, a parity for data scrambling and error detection is also applied thereto, and the mixed data is finally 8-to-16-modulated and output. A data storage unit 110 is required to perform the channel encoding. A technique associated with the above-described channel encoding departs from the core of the present invention, so a detailed description thereof is found in Korean Patent Application No. 96-69200.
A data bitstream output from the channel encoder 103 is modulated by a laser power modulator 104 before it is recorded on the disk 109. As a recording/reproducing switch 130 is switched to a recording mode, the output of the laser power modulator 104 is recorded in the disk 109 by an optical pickup 105. The focusing/tracking of the optical pickup 105 is controlled by a focusing/tracking servo unit 106. The optical disk 109 is rotated by a spindle motor 108 under the control of a spindle servo unit 107.
Data reproduction is performed by reversing the order of steps used in data recording. When a data reproduction command is applied, the recording/reproducing switch 130 is switched to a reproduction mode. Thus, a radio frequency (RF) amplifier 111 amplifies a weak, read signal detected by the optical pickup 105, to an appropriate gain. A channel decoder 112 performs error detection and error correction on the basis of the preset reverse process of channel encoding, and performs 8-to-16 demodulation.
Thereafter, a data parser 113 parses the output of the channel decoder 112 into video data and audio data. A video decoder 114 and an audio decoder 115 decode the video data and the audio data, respectively.
Accordingly, a television (TV) signal encoder 116 encodes the output of the video decoder 114 into a TV image signal of a standard such as NTSC, PAL or SECAM, and displays a video signal via a monitor 118. Simultaneously, a digital-to-analog converter (DAC) 17 converts the output of the audio decoder 115 into an analog audio signal and outputs the analog audio signal via a speaker 119.
In such a conventional disk recording and reproducing system, when a moving picture such as a movie or TV program is consecutively recorded using an optical disk recording apparatus, users cannot directly access a specific portion of the recorded moving picture.
To solve the above and other problems, an object of the present invention is to provide a direct accessing apparatus and method in a disk recording and reproducing system, in which a specific image is periodically captured from an input video signal consisting of a sequence of specific images which when suitably displayed give the appearance of a moving or continuous image, each captured image is edited with information including information on the positions of areas of a disk on which the specific images are recorded, and a resultant image (the image index information) is recorded on a specific area of the disk. The image index information is utilized as visual index information in a reproduction mode, so that users can directly access the position of a desired moving image.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and, in part, will be obvious from the description, or may be learned by practice of the invention.
Accordingly, to achieve the above and other objects, the present invention provides a direct accessing apparatus in a disk recording and reproducing system, including a video encoder, an image capturer, a microprocessor and an index image storage unit. The video encoder receives and encodes video data consisting of a sequence of specific images as a data recording command is applied. The image capturer periodically captures video data corresponding to a specific or still image from the encoded video data. The microprocessor records the encoded video data on the disk as a continuous image consisting of a sequence of specific images, receives and edits the outputs of the image capturer in units of a screen, generates image index information including information on the positions of areas of a disk on which each specific image corresponding to a captured image is recorded in the continuous images, records the captured images and the image index information on a specific area of the disk, in a recording mode, and directly accesses the continuous image beginning at the position on the disk where a specific image corresponds to a captured image. The index image storage unit stores the captured images and the image index information.
To achieve the above objective, the present invention provides a direct accessing method of a disk recording and reproducing system, comprising the steps of: (a) receiving and encoding video data as a data recording command is applied; (b) capturing still images from the encoded video data at predetermined time intervals; (c) receiving and editing the captured still images in units of a screen to enable a continuous image including the still images to be visually indexed, and storing image index information including information on the positions of areas of a disk on which the still images are recorded, by matching the image index information with the still images; (d) editing and recording the image index information on a specific area of the disk, after all of the video data on the disk is completely recorded; and (e) determining the addresses from which the continuous image is to be reproduced from the disk, by reading the still images recorded on the disk, and directly accessing the continuous image at an address corresponding to the read still images, in a video reproduction mode.